Height adjustable backrests are commonly employed on secretarial chairs or the like, and a variety of backrest adjusting and locking mechanisms for such backrests are known in the prior art. In most instances, the prior art adjusters are fairly costly and commonly have protruding knobs, operating levers and the like which are somewhat unsightly and sometimes inconvenient. Some examples of the prior art are shown in the below-listed U.S. patents which are made of record herein to comply with the duty to disclose known prior art under 37 C.F.R. 1.56, U.S. Pat. Nos.:
2,054,557 PA1 3,326,602 PA1 3,351,379 PA1 3,526,430 PA1 3,854,772 PA1 4,012,158 PA1 4,043,594.
The objective of the invention is to provide a chair backrest adjuster which is entirely free of the above-noted deficiencies of the prior art, and which is considerably less costly to manufacture, more convenient to use, and provides a much better finished appearance on the chair which employs the invention. A further attribute of the present invention resides in a simpler and less costly assembly procedure for the backrest which is equipped with the push button adjuster in accordance with the invention.
Other features and advantages of the invention will appear to those skilled in the art during the course of the following description.